This proposal describes a consortium application for organization of a multi-institutional Massachusetts region Huntington's Disease Center Without Walls. More than 2500 persons either with Huntington's Disease or their family members, many of whom are at risk for the disease, are available in the registry of the Massachusetts Chapter of the Committee to Combat Huntington's Disease. It is proposed that medical care for these patients and their family members be organized in clinics located in the medical centers of each of the four Massachusetts medical schools; University Hospital-Boston University, Massachusetts General Hospital, Peter Bent Brigham Hospital, Tufts New England Medical Center and the University of Massachusetts Medical Center. Organization of these facilities for the triage of patients to appropriate specialists within the Center, for the collection of tissue samples for research and, in the event of death, for neuropathologic examination is described. Clinical and basic laboratory research will be conducted by established scientists and projects are described which will capitalize on the development of new technologies in the areas of molecular genetics, peptide neurochemistry, immunological neuropathology, neuropharmacology, analytical biochemistry and positron emission topography. Clinical research activities will be coordinated with the Massachusetts Chapter of CCHD and the individual H.D. clinics and will involve data registry, social and genetic counseling, psychological and psychiatric evaluation and physiological testing, with special attention to assessment of juvenile cases of the disorder. Critical attention will be paid to the ethical issues associated with presymptomatic testing. We believe that the cooperation that has been achieved to involve all of the university medical centers of Massachusetts in the proposed studies makes this application for a Center Without Walls particularly strong and valid.